Carburetor



Oct. 12, 1937. M. E. CHANDLER 2,095,233

.CARBURETOR Filed Jan'. 21, 1955 INVENTOR ATTORNEY `Patented Oct. 12, 1937 UNITED STATES CARBURETOR Milton E. Chandler, Detroit, uMich.

Application January 21,`l935, Serial No. 2,682

9 Claims.

` Object of this invention is to design a carburetor of a novel form which will have distinct advantages over carburetors now in use. The carburetor will lend itself particularly well to the requirements of aircraft engines and to the requirements of the high efficiency engines that are now being used.

Carburetor design has in the past follo'wed more or less distinct trends. For a time the pop- 'ular carburetor in use had fuel orifices of fixed size and the air openings automatically variable as a function of air ow through the carburetor. Later variable fuel orices were used with the automatically variable air openings. It was difcult with these carburetors to obtain maximum torque owing to the restriction of the air valve and likewise to the fact that the air passages were not of uniform cross-section and the distribution of air and fuel was bad. Later this type of carburetor was replaced in popularity with carburetors of a so-called plain tube type having a fixed air orifice and a ixed fuel orifice. These carburetors were and are very popular and efficient, but as engine output per cubic inch increased the air orice became so large thatit was dilcult to get good flexibility on account of the low suction on the fuel nozzle at low air flows and it was necessary to add various devices to cover up the inherent deficiencies of this type of carburetor. The plain tube carburetors, the same as the air valve carburetors, likewise had air passages that were not uniform in cross-section and trouble has likewise been encountered in getting good distribution and power. The conventional buttery throttle between the ixed air orice and the intake manifold likewise contributed. to. poor distribution at some throttle openings.

In this invention the air openings will be mechanically variable as a function of the power demanded and the'fuel orifice will likewise be variable as a fixed function of the position of the air opening. The ordinary throttle is dispensed with and the variation in the opening of 'the air passage mechanically controlled constitutes the only control of air opening or throttling. In this invention the air openings or passageways are symmetrically arranged on either side of a vertical plane longitudinal with the carburetor or a 9 vertical plane crosswise with the carburetor. The air will therefore always at all throttle openings travel a uniform path and will not be deflected by non-uniform sections of the air passage.l

The carburetor will meter as a plain tube car` buretor for every position of the Venturi throttles, for at every position of the throttle there is a proper size of fuel orifice to correspond therewith. The fuel is always discharged through one discharge nozzle and the lag that occurs in o transferring from the idle in the plain tube carburetor to the main jet will not be evident. The present so-called plain tube carburetors mechanically meter during the idle range andup to about twenty-five miles per hour. This rnechanical metering is crude and di'cult to control. At speeds above twenty-five miles an hour and up to about seventy miles per hour the metering is primarily a function 'of air ow and beyond this and up to maximum speed it is a combined function of air ow and mechanical means. With the new design the fuel ratio is mechanically controlled for every throttle position in a simple and accurate manner. For a given throttle posi- 'tion and a variable air flow it will meter purely as a function of air flow. These characteristics -will make it easy to obtain the desired air and fuel mixture ratios. f

Figure 1 is a cross-sectional plan` view taken on plane I--I of Figure 2.

Figure 2 is the end view of Figure l.

Figure 3 shows the cross-sectional elevation taken on plane 3--3 of Figure 2, but showing the construction shown in Figure 1 modified so as to produce a duplex construction.

Figure 4 is a cross-sectional elevation taken on plane l-t of Figure 1.

vFigure 5 shows a detail of the nozzle control for the construction shown in Figure 3.

Figure 6 shows an alternative method of controlling the fuel flow. Fig. 7 shows an elevation on plane l-ll of Figure 3.

Describing the embodiment of my invention shown in Figures 1, Zand 4, the air entrance is shown at lll surrounded by walls it and the mixture outlet is shown at II. Two cylindrical throttles I2 and I3 mounted on bearings, located in end walls Iii and 42,-are shown geared together with a set of gears It and Il and adapted to engage with a horizontal fuel passage 2l, so as to provide two rectangular openings on each side of the passage 2l.

The fuel supply to a fuel passage 20 is obtained through a vertical passage I9 which communicates with a float chamber I8, the float-mechanism details of which are not shown.

The fuel supply is regulated by means of a restriction 2l and a needle valve 22, both mounted in the passage 2li. The needle valve 22 is moved in unison with the movement of the two throttles I2 and I3 by'means of a cam 24 which engages with a lever 23, which is pivoted to an end wall 42 of the carburetor, on a pin 33 mounted in the wall 42, the lever 23 engaging with the needle valve 2I. A spring is mounted in the passage 20 andI its function is to take up any backlash there may be in the mechanism. The fuel ows from the upper fuel passage 20 through the restriction 2I,`

vto the lower fuel passage 21, thorugh across passage 26. The lower passage 2l is perforated at 28 to provide fuel outlets into the mixing cham- `orifice 26 to the interior of the bellows 3|.

ber. Fuel thus issues into the throat of the variable venturi of rectangular form, between the throttles I2 and I3 and the transverse horizontal fuel passage 2l.

Describing next the duplex construction shown in Figures 3 and 5, the cylindrical throttle I3 is provided with a web 34 which divides the venturis into two. The mixture outlet II is divided into two equal rectangular portions II'-I I", by means of a vertical wall 30. This wall 30 is in alignment with the web 34. The two mixture outlets II-I Ill are thus separated by the web 34 on the throttle I3 and, of course, a corresponding web, not shown, on the corresponding throttle I2.

In Figure 3 the fuel discharges past the restriction 2I, and is assisted by an air vent 35, located in the air entrance I0, which admits a jet of air, which sweeps over the restricted outlet from the orice 2|, and discharges atomized fuel and airv through the passage 26 into thehorizontal passage 21, which discharges into the throat of the two venturis through the outlets 28 and 29.

Figure 5 shows a modification of the air vent 35. A spring loaded airvalve 25 is used to restrict the flow of air which mingles with the fuel issuing from the restriction 2| and flowing through the communicating passage 26 into the horizontal fuell passage 21, whence the fuel and air is discharged as before through the outlets 28 and 29.

In Figure 6 a sylphon bellows 3| is shown located between the needle 22 and its operating lever 23. A passage 32 in the center of the needle 22 admits the depression or vacuum in the fuel manifold 21 to the interior of the sylphon bellows 3|, whereby the fuel restriction 2| is automatically closed when an excessive suction is transmitted from the mixing chamber around the manifold 21 through the orifices 29 and 28 and through the By this means compensation is obtained at high air flows to prevent an excessively rich mixture which would otherwise be formed due to the fact that air is an elastic medium and liquid gasoline is not.

What I claim is:

1. A carburetor comprising a symmetrical mixture outlet, a symmetrical air entrance located on the same axis as said outlet, two symmetrical rollers having parallel sides adapted to roll together so as to act as throttles and also to form a variable symmetrical rectangular mixing chamber of Venturi form located between said air entrance and said mixture outlet and having an axis parallel to the axis of said air entrance, a fuel nozzle located so as `to discharge at all times into the throat of said variable rectangular venturi, a, needle controlled by the movement of said rollers and adapted to control the ilow of fuel to said nozzle, and means controlled by the depression in said venturi for moving said needle independently of said rollers.

2. A duplex carburetor having two similar rectangular air passages controlled by two similar cylindrical throttles adapted to roll together so as to act as the throttles and also to form two variable rectangular Venturi openings therebetween, a common fuel passage, a source of fuel supply leadingthereto, a restriction in said aassage, a second fuel passage connected thereto beyond the point of restriction therein, said second fuel pa'ssage extending transversely across said'Venturi openings, a plurality of fuel outlets discharging into the throats of said Venturi openings.

3. A carburetor comprising a carburetor body, a pair of streamlined symmetrical rollers mounted therein, the surfaces of which are parallel to their axes, means for rotating them together so as to form a variable Venturi opening of rectangular construction therebetween in said carburetor body, fuel supply means, a. main fuel discharge passage connected thereto and extending completely across said variable Venturi opening on an axis parallel to the axes of the two rollers and located symmetrically with reference thereto so as to divide the throat of the venturi into two equal and similar rectangular openings, and lateral fuel outlets from said fuel passage discharging into the throat of each of said rectangular Venturi openings at its point of minimum area.

4. A carburetor as defined in claim 3, in which the ilow of fuel in said fuel passage is controlled by a needle valve operated in unison with said rollers.

5. A carburetor comprising a carburetor body, a pair of symmetrical rollers, the surfaces of which are parallel to their axes, mounted therein, means 'for rotating them together so as to form a Variable Venturi opening of rectangular construction therebetween in said carburetor body, fuel supply means, a fuel passage leading therefrom, a restriction therein, a second fuel passage connected to the rst fuel passage on the downstream side of said restriction andF4 extending completely across the Venturi opening on an axis parallel to the axes of the two rollers and located so as to divide the throat of the venturi into two equal and similar rectangular openings, and lateral fuel outlets from said second fuel passage discharging into the throat of each of said rectangular Venturi openings at its point of minimum area.

6. A carburetor as defined in claim 5 with an atmospheric opening into said rst fuel passage adjacent to said restriction and adapted to aspirate the fuel issuing therefrom.

'7. In a carburetor, a mixture chamber, a mixture outlet, an obstruction having a fuel passage therein extending transversely across the center of said mixture chamber, throttle means located in said chamber on each side of said obstruction and engaging therewith so as to form two variable mixture openings between the obstruction and the throttles, said openings forming at all times the sole restriction to the flow of mixture through said carburetor, an unobstructed passage connecting said sole restriction with the mixture outlet, and lateral fuel outlets from said fuel passage into said variable mixture openings.

8. In a carburetor as set forth in claim 7, a stationary transverse partition separating the mixture chamber into independent equal halves, and movable partitions mounted on said throttles in alignment with said stationary partition for the purpose rdescribed.

9. In a carburetor as set forth in claim 7, means for dividing the mixture chamber into a plurality of separate independent mixture chambers of equal area, said means including at least one stationary partition arranged transversely to the axis of the'throttles and at least two movable partitions foreach stationary partition mounted on said throttles in alignment with said stationary partition separating the mixture chamber into a plurality of independent equal portions.

MILTON E. CHANDLER. 

